The Effect Of Edaravone On EAE And The Expression Of INOS,OPN In Rats Of EAE

Objective To study the effect of edaravone on experimental autoimmune encephalomyelitis(EAE) in rats and elucidate the role of the inducible nitro oxide synthase and Osteopontin in EAE so as to provided evidences for the treatment of multiple sclerosis.Methods 72 adult healthy female Wistar rats were randomly divided into four groups: normal grou(pN group), EAE group, low-dose edaravone group(LDE group), large-dose of edaravone group(HDE group)( n = 18). All the groups were divided into three subgroups : 7 day group, 14 day group and 21 day group. The EAE group,LDE group and HDE group experimental rats were immunized subcutaneously in the four foot pads and back with emulsion 0.5ml,which including fresh guinea pig spinal cord homogenate(GPSCH) as antigen,emulsified with an equal volume of complete Freund's adjuvant (CFA) containing Mycobacterium tuberculosis 10mg/ml. Meanwhile, three group rats were injected subcutaneously in the four acrotarsiums with Bacillus pertussis 0.4ml . Normal group, low dose of edaravone group and high dose of edaravone group were injected intraperitoneal respectively NS 0.5ml/d,edaravone 4mg/kg.d,edaravone 10mg/kg.d .These treatments were started on the first day of immunization and continued daily for the duration of the experiment,and EAE group left untreated. During the experiment, the incidence and the scores of neurologic impairment were recorded,also the HE staining, iNOS and OPN immunohistochemistry staining were performed and analyzed.Results1.Incidence of disease in different group: No ill rats in normal group .The incidence of EAE group was 83.33%. Either low or large-dose edaravone group ,the incidence of EAE was significantly less than the EAE group(P <0.05). Moreover,in larger-dose edaravone group,the incidence of disease was less than low-dose edaravone group (P<0.05).2.Ethology appraisal in different group:The neurological function score of normal group,low-dose of edaravone group and high-dose of edaravone group were significantly lower than those of EAE group at the 14th day of immunization (p<0.05).3.Histopathological findings: There was no inflammatory cell infiltration in the normal group, but the inflammatory cell was found in the spinal cord of the each stage group of EAE group,low-dose of edaravone group and high-dose of edaravone group. The results demonstrated that some inflammatory cell infiltration was observed in the tissues of spinal cords before the clinical signs emerging.The degree of infiltration was associated with the severity of EAE. At the 14th day of immunization ,the nurnber of inflammatory cell of normal group,low-dose of edaravone group and high-dose of edaravone group were significantly lower than that of the EAE group (P <0.05),and that of high-dose of edaravone group was lower than the low-dose of edaravone group group (P <0.05). At the 21th day of immunization, the nurnber of inflammatory cell of normal group and HDE group were lower than that of the EAE group (P <0.05).?4.The expression of iNOS and OPN: There was no the iNOS and OPN immuno-positve cell in spinal cord of the normal group; but the iNOS and OPN immuno-positve cell could be seen in the spinal cord of EAE group,low-dose of edaravone group and high-dose of edaravone group. At the 14th day of immunization, the number of the iNOS and OPN immuno-positve cell of normal group,low-dose of edaravone group and high-dose of edaravone group were significantly lower than that of the EAE group (P <0.05),and that of high-dose of edaravone group was lower than the low-dose of edaravone group group (P <0.05). Conclusion1.The expreesion of iNOS and OPN correlated with the severity and activity of EAE.With the development of the disease,the expreesion of iNOS and OPN kept increasing.In the recovery of EAE,their levels had declined.2. Administrate edaravone treatment on EAE could drop the incidence of EAE rat and ameliorates the severity of EAE before the onset of EAE.3. The results suggested that Edaravone have protective role on EAE, which can clearance of free radical,alleviation of inflammatory reaction and reduction of the expression of iNOS and OPN.